The invention relates to a high-pressure discharge lamp provided with
a discharge vessel with a ceramic wall which encloses a discharge space, PA1 a filling comprising at least a rare gas and a metal. PA1 an electronic circuitry unit.
The invention also relates to an electronic circuitry unit suitable for igniting and operating the high-pressure discharge lamp.
A lamp of the kind mentioned in the opening paragraph is known from EP-A-0 215 524. The known lamp is a metal halide lamp whose discharge vessel contains at least one metal halide. The known lamp is very suitable as a light source for inter alia interior lighting for, for example, shop windows, sports halls, etc., also because of its comparatively small dimensions. The light radiated by the lamp has very good photometric properties, such as a color temperature in the range from 3000 K to 4000 K, a color rendering index value Ra of 80 or higher, and a high luminous efficacy.
In the present description and claims, the term "ceramic wall" is understood to refer to a wall made of metal oxide such as, for example, sapphire or densely sintered polycrystalline Al.sub.2 O.sub.3, or of metal nitride, for example AlN. The discharge vessel contains one or several metal halides and at least one rare gas as its filling ingredients. In addition, the known lamp also contains mercury as a filling ingredient. Although the lamp seems to be highly suitable for miniaturization on account of the small dimensions of the discharge vessel, a separate circuitry unit remains necessary for operating the lamp. This is a disadvantage hampering a wide application range of the lamp.